Vacuum cleaner



Nov. 19, 1935. A. A. FoRsBERG I VACUUM CLEANER 2 Sheets-Sheet 1 Filed Feb. 25, 1955 A. A. FoRsBERG VACUUM CLEANER Nov. 19,1935.

' 2 sheets-sheet 2 Filed Feb. 25, 1933 Patented Nov. 19, 1935 UNITED STATES 2,021,298 VACUUM CLEANER Axel Albert Forsberg,

stdckholm, sweden, as-

signorto Electrolux Corporation, Dover, Del., a corporation of Delaware Application February 25, 1933, Serial No. 658,608

In G

17 Claims.

My invention relates to vacuum cleaners and particularly to means for reducing the noiseand vibration in a vacuum cleaner having a vertically arranged motor-fan unit.

In a vacuum cleaner wherein the motor-fan unit is arranged vertically and the air is drawn in at the top of the fan and expelled from the bottom thereof, there are two oppositely directed forces acting on the unit when the latter is in operation. First, there is the weight of the unit which acts vertically downwardly and is constant. Second, there is the force resulting from the air pressure difference created by the fan which, with the direction of flow as described,

d acts vertically upwardly. This second force varies with variations in the suction produced by the fan, which, although the fan speed is constant, is caused to vary by changes in the resistance to flow of the air. Such a change occurs, for instance, when the nozzle or other cleaning implement is removed from a surface being cleaned.

Slighter changes occur almost constantly during' the` operation of the lcleaner as the cleaning implement is moved over such surface. These changes, which affect the forces acting on the motor-fan unit, cause the latter to vibrate and thus to produce noise.

In accordance with my invention I propose to support the motor-fan unit within acasing in such manner that the air pressure difference created by the fan lifts the unit, and I resist such upward movement of the unit by resilient means. Hence, the motor-fan unit floats, so to speak, in the air` stream produced by the fan and is able to move vertically upon changes of the suction effect produced by the fan, without such movement being communicated to the casing of the vacuum cleaner. Hence, substantially all of the vibration is confined to the motor-fan unit, which results lin a quieter operation of the vacuum cleaner.

Further objects and advantages of my invention will be apparent from the following description considered in connection with the accompanying drawings, which form a part of this speciflcation and on which:

Fig. l is an elevational cross-sectional view of .a vacuum cleaner including one embodiment of my invention;

- Fig. 2 is a cross-sectional view of a portion of thev vacuum cleaner similar to that shown in full in Fig. 1, but including another embodiment of my invention; and

Fig. 3 is a. cross-sectional view of a portion of a vacuum cleaner similar to that shown in full in Fig. `1, but including a .third embodiment ofA my invention. v

Referring more particularly to Fig. 1, reference character III designates an annular base member provided with a caster I I and a pair of small ermany March 14, 1932 (Cl. 18S- 37) wheels I2 for supporting it on a surface. A second annular member I3 is spaced above member I0 by means of an outer cylindrical member I4 and an inner cylindrical member I5. Member I4 is provided with louver openings I6for the discharge therethrough of air. A circular plate I1 is supported by member III and serves to'close the circular opening in annular member I0. A hose coupling member I 8 is secured in cylindrical member I4 and is provided for the connection thereto 10 of a hose or the like when it is desired to use the apparatus for blowing.

A motor casing I9 is provided with a lower annular flange which is supported by and secured to member I3. .The upper part of casing I9 is 15 provided with an opening 2l which serves as an inlet for air. A ring-shaped cushion of rubber, leather or other similar material 22 is secured aroundl the periphery of opening 2 I. A rigid yoke member 23 is adapted to rest on cushion 22. A 20 plurality of springs 24 are secured at their upper ends to the extremities of yoke 23 and at their lower ends to casing I9. In the embodiment shown, the casing is provided with vertical slots in which-the springs 24 are located andwith 25 vapertures below 'the lower ends of the slots to receive the lower ends of the springs. The various parts are so dimensioned that, when the yoke 23 is resting on cushion 22, the springs 24 are stressed very slightly, if at all.

A plurality of springs 25 are secured to yoke 23 and extend through openings formed in the top of casing I9. The lower ends of springs 25 are suitably secured to the frame of an electric motor 26, the axis of which is arranged to extend in a vertical direction. 'Ihe upper end of the motor is provided with a 'cushion member 21 of rubber, leather or the like. Springs 25 are so designed that, when placed under tension due to the 4weight of the motor unit, there is a space 40 between cushion 21 and that portion of yoke 23 which is directly above it, and that, when the motor is moved up, as will be described later, so ythat cushion 21 contacts yoke 23, springs 25 are under little or no tension.

The motor 26 is provided with an armature shaft 28 to which is secured for rotation therewith a centrifugal fan 29 comprising, in the emy bodiment shown, three rotors. A fan housing 36 is secured to the motor housing by means of brackets 3| and serves'to enclose all except the lowermost rotor of the fan. Motor 26, fan 29 and housing 3|! comprise what may be termed a motor-fan unit. A flexible sealing member 32 of generally annular configuration is secured to the upper part of fan housing 36 and to casing I9. This sealing member prevents the back flow of air from the discharge of the fan to the intake thereof and makes possible the existence of different pressures on eithenside of the sealing member. It will be noted that the upper surface 33 of the fan housing, bounded by sealing member 32, is greater than the cross-sectional area of the air. inlet 2|. If the upper part of .the

ian housing were not horizontal but, for instance,

cone shaped, it would be the projection of this surface on a horizontal plane which should be greater than the inlet opening 2|. It is this horizontal area of the fan housing against which 'the air pressure difference created by the fan acts to raise the motor-ian unit. In order that the force so produced shall be sufficient to overcome the weight of the motor-fan unit, the respective areas are preferably proportioned -as above described.

A dust receiving receptacle 34 comprises an outer cylindrical part 35, a lower annular portion 38 and an inner cylindrical portion 3l! connected to a conduit 99. Cylindrical portion 31 surrounds motor casing I9. An inlet opening 89 is provided near the upper part of dust receptacle 34 and'is adapted to' receive a hose lor the like leading from a suitable cleaning implement. Receptacle 34 is supported on an lnturned portion of cylindrical member I4 and on a packing 40 secured to casing i9. Packing 40 vcomprises a ring of rubber or the like and effects an air'- tight seal.

The upper end of conduit 38 is in thekplane of the upper end of the louter cylindrical portion 35 of receptacle 34. The upper edge of cylindrical portion 35 is formedl with an out-turned ilange upon which rests a ring 41 provided with a packing ring of rubber or the like so as to provide an air-tight seal. Ring 41 carries a circular dust separating member 48 made of cloth which is pervious with respect to air but prevents the passage therethrough of dust particles. The center of member' 49 is provided with an opening surrounded by a ring 49 adapted to rest on the anged upper end of conduit 38. Ring 49 is provided with a packing ring of rubber or the like in order to effect an air-tight seal. A cover member 50 rests upon ring 41 and clamps it Cover member 50 is held in A spiral against ange 48. place by means of catch members 5I.

spring 52 is secured to the center of cover memvis secured to the top cover member 50.

The dust separating member 48 per se constitutes no part of the present invention and may be replaced by any other suitable dust separating member, such, for instance, as that shown in application Serial No. 594,181 of Tom C. Bieth, led February 20, 1932, which has since matured into Patent No. 1,946,665dated Feb. 13, 1934.

The operation of the above described device is as follows:

When the motor and fan are ngt rotating the weight of the motor-fan unit-is carried by springs 25 which, when under tension caused by such weight, supports the cushion 214 on the top of motor 28 a short distance below yoke 23. When the fan is rotated it creates a partial vacuum in the chambers communicating with the inlet of the fan. 'I'his causes air to flow inwardly through the cleaning i/rnplement and hose attached to j inlet opening 39 and, if the cleaning implement is moved over a dusty surface, this air is laden with dust. The Idust thus introduced into receptacle 34 is deposited within the receptacle while the air itself passes upwardly through dust separating member 48 and intov cover member 58. From here the air passes downwardly through conduit 38, through opening 2| to within the motor casing and thence to the inlet of the fan housing. The fan discharges the air into the space between cylindrical members I4 and I5 and the air escapes through louver openings I6.

There is thus produced in the motor casing a partial vacuum, while the air outside of the fan housing is under somewhat greater than atmospheric pressure. This air pressure difference tends to raise the entire motor-fan unit until cushion 2l strikes yoke 23. dltions springs 25 are under little or no tension. Further upward movement of the motor-fan unit, caused by this. air pressure diierence, lifts yoke 23 upwardly from ring 22 against the resistance offered by springs 24. The motor-fan unit comes to rest at such a point that this upward force is balanced by the tension of springs 24. The motor-fan unit is thus floating, so to speak, in the air stream produced by the fan.

The greater the resistance to flow of air into the vacuum cleaner, the greater will be the suction eiect produced by the ian, and hence the greater will be the air pressure difference. As the cleaning implement is moved over the surface to be cleaned, this resistance to flow varies. This causes the upward force acting on the mo- Under these contor-fan unit to vary, which in turn causes the 'i pressure diiierence has been built up to lift the motor unit, vibration would be communicated to the stationary parts of the vacuum cleaner, wherefore it is preferred to employ resilient means to support the motor from yoke 23.

In the modification shown in Fig. 2, the frame .f'

of motor 28 is provided with eyes 54,`or other suitable means to which may be secured the ends of springs 55 and 58. The lower ends of 'springs 55 are secured to eyes 54 while the upper ends of these springs are secured to pins 51 which extend lthrough openings in casing I9 and are provided at their upper ends with enlarged portions v58. The upper ends of springs 58 are secured to eyes 54 while the lower ends are secured to pins 59 which extend through openings in an annular ,3

upwardly, springs 55 become unstressed and pins- 59 move upwardly through the openlngsin ring 80 until the enlarged portion 8| abuis against the underside of the ring, whereafter'further uplWard movement of the unit is resisted by springs 58,which are thus stressed. Under these conditions, the motor-fan unit is oating In the air stream produced by the fan and is connected to the stationary parts of the cleaner only the stressed springs 58.

In the embodiment shown in Figs. 1 and 2 there through GLS have been shown one pair of springs for supportlng the motor-fan unit when not in operation and one pairv of springs for resisting upward movement of-the unit when in operation. Obviouslyfinstead of employing pairs of springs, there can be used springs in sets of three or any desired number distributed equidistant around the periphery of the motor.

In the modification shownin Fig. 3 a single spring is employed for both supporting the weight of the motor when not operating and for resisting the upward movement of the motor-fan unit when operating. In this embodiment the motor 26 is provided at its upper end with an extension 62. The upper end of extension 62 is provided with an enlarged "flanged member 63 which is adapted to engage a spring 64 intermediate of the ends of the spring. The upper end of spring $4 is secured to a flanged member 65 which is adapted to rest on the upper end of casing I9. The lower end of spring 64 is secured to a flanged member 6B which is adapted to abut against a flange 61 carried by casing i9.

When the motor-fan unit is not operating it is supported by the upper part of spring 64 acting through flange 65 which rests upon the top of casing i9. Under these conditions, the` lower part of spring 64 is not under stress and flange 66 is some distance below flange 61. When the air pressure difference createdby the fan over-- comes the weight of the motor-fan unit and moves the latter vertically upwardly, the upper part of spring 65 becomes unstressed at substantially the same time that flange 66 strikes flange 61. Further upward movement of the unit is resisted by the lower portion of spring 64 which is now placed under tension. Under these conditions the motor-fan unit is floating in the air stream produced by the fan and the only connectionrbetween the unit and the re'stof the cleaner is through the lower part of spring 64.

In all of the modifications it will be noted that the springs are either not stressed or are under tension. None of the springs are-ever under compression. Due to this fact, no means are necessary to prevent the springs from buckling. as they would do if they were subjected to force of compression.

While I have ments of my invention, these have been selected for purposes of illustration only and my invention is not to be limited thereto, but its scope is to be determined by the appended claims viewed in the light of the prior. art.

What I claim is:

1. In a vacuum cleaner, a motor-fan unit comprising an electric motor having a vertically extending armature shaft and a fan mounted on said shaft, means for supporting said unit so as to permit upward movement of said unit due to 'the air pressure difference created by said fan,-

and resilient means for resisting said upward movement.

2. In a vacuum cleaner, a motor-fan unit comprising an electric motor having a vertically extending armature shaft and a fan mounted on said shaft, resilient means forv supporting said unit so as toH permit upward movement ofl said v unit due to the air pressure diilerence created by said fan, and resilient means for resisting said upward movement.

3. In a vacuum cleaner, a stationary casing, a

motor-fan unit comprising an electric motor within said casing and having a vertically extendingfarrnature-shaft and a fan mounted on described three preferred embodisaid shaft, means for supporting said unit from` said casing so as to permit upward movement of lsaid unit with respect to said casing due to the air pressure difference Lcreated by said fan, and resilient means reacting between said casing and said unit for resisting said upward movement. 4. In a vacuum cleaner, a stationary casing, a

' motor-fan unit comprising an electric motor within said casing and having avertically extending armature shaft and a fan mounted on said shaft, means for .resiliently supporting said unit from said casing so as to permit upward movement of said unit with respect to said casing due to,` the air pressure difference created by said fan, and resilient means reacting' between said casing and said unit for resisting said upward movement.

5. In a vacuum cleaner, a stationary casing, a motor-fan unit comprising an electric motor within said casing and having a vertically extending armature shaft and a Ian mounted on said shaft, a rigid member supported by said casing so as to be movable in a vertical direction, means for supporting said unit from said member, and resilient means between said casing and said member for resisting upward movement of said member.

6. In a vacuum cleaner, a stationary casing, a motor-fan unit comprising an electric motor within said casing-and having a vertically extending armature shaft and a fan mounted on said shaft, a rigid member supported by said casing so as to be movable in a vertical direction, resilient means for suspending said unit from, and in spaced relationship below, said member whereby upward movement of said unit due to the air pressure difference created by said fan causes said unit to abut against said member, and resilient means between said casing and said member for resisting upward movement of said member.

7. In a vacuum cleaner, a stationary casing having an air inlet opening inthe upper part thereof,l a motor-fan unit comprising an electric motor within said casing having a vertically extending armature shaft, a fan mounted on said ing greater than the cross-sectional area of said flinlet opening, means for supporting said unit from said casing so as to permit upward movement of said unit with respect to said casing due to the air pressure difference created by said fan,

and resilient means reacting between said casing i and said unit for resisting said upward movement,

8. In a vacuum cleaner, a stationary casing, a motor-fan unit-comprising an electric motor within said casing and having a vertically extending armature shaft and a fan mounted on said shaft, resilient means secured at the upper end to said casing and at the lower end to said unit for supporting`said unit, and resilient means secured at the upper end to said unit and at the lower end to said casing for resisting upward movement of said unit caused by the air pressure difference created by said fan.

9. In a vacuum cleaner, a stationary casing,

a motor-fan unit comprising an electric motor at their upper ends to said casing and at their lower ends to said'unit for supporting said unit,

li) -Y and a plurality of springs secured at their upper ends to said unit and at their lower ends to said casing for resisting upward movement of said unit caused by the air pressure difference created by said fan.

10. In a vacuum cleaner, a stationary casing, a motor-fan unit comprising an electric motor within said casing and having a. vertically extending armature shaft and a fan mounted on said shaft, a plurality o f springsl secured at ytheir lower ends to said unit and at their upper ends to said casing for supporting said unit, the upper ends of said springs having limited movement with respect to said casing, a plurality of springs secured at their upper ends to said unit and at their lower ends to said casing for resisting upward movement of said unit caused by the air pressure difference created by said fan, the lower ends of said last mentioned springs having limited movement with respect to said casing.

l1. In a vacuum cleaner, a stationary casing, a motor-fan unit comprising an electric motor within 'said casing and having a vertically extending armature shaft and a fan mounted on said shaft, a spring secured intermediate of its ends to said unit, means secured to the upper end of said spring and adapted to rest on said casing for supporting said unit, .and means secured to the lower end of said spring and adapted to abut against said casing for resisting upward movement of said unit caused by the air pressure difference created by said fan.

12. In a vacuum cleaner, a base portion, a dust receiving receptacle supported on said base portion, said receptacle formed with an annular lower part, a easing supported on said base portion and extending into the space surrounded by said lannular lower part, a conduit extending upwardly from said space, means for causing air to flow into said conduit, said receptacleformed with an air inlet opening, a motor-fan unit comprising an electric motor within said casing having a vertically extending armature shaft and a. fan mounted on said shaft, means for supporting said u nit from casing so as to permit upward movement of said unit due to the air pressure diierence created by said fan, and resilient means reacting between said casing and said unit-for' resisting said upward movement.

13. In a vacuum cleaner, a base portion, a dust receiving receptacle supported on said base portion, said receptacle formed with an annular lower part, a casing supported on said base portion and extending into the space surrounded by said annular` lower part, a conduit extending upwardly from said space, means for causing air to iiow into said conduit, said receptacle formed with an air inlet opening, a motor-ian unit comprising an electric motor within said casing hav-y said annular lower part, a conduit extending une` wardly from said space, means for causing air tooflow into said conduit, said receptacle formed with an air inlet opening, a motor-fan unit comprising an electric motor within said casing hav- 5 ing a vertically extending armature shaft, a i'an mounted on said shaft and a housing around said Ian and supported by said motor, ilexible sealing means between said housing and said casing, means for supporting said unit from said casing l so as to permit upward movement of said unit due to the air pressure difference on either side or said sealing member created by said fan, and resilient means reacting between said casing and said unit for resisting said upward movement. l

15. A vacuum cleaner comprising a, dust collecting receptacle having impermeable walls and having a passageway extending through the same, a casing within a part of said passageway, a. motor-fan unit comprising an electric motor in said casing having a vertically extending armature' shaft and a fan mounted on said shaft to draw air through said passageway, means to admitair to said receptacle, afJcover removably secured to said receptacle and serving to direct air from 2 within said receptacle to said passageway, means for supporting said unit from said casing so as to permit upward movement of said unit due to the air pressure difference created by said fan, and resilient means reacting between said casing and said unit for resisting said upward movement.

16. A vacuum cleaner comprising a dust col` lecting receptacle having impermeable walls and having a passageway extending through the same, a casing within a part of said passageway, a motor-fan unit comprising an electric motor in said casing having a vertically extending armature shaft, a fan mounted on said shaft to draw air through said passageway and a housing around said fan supported by said motor, means to admit air to said receptacle, a cover removably secured to said receptacle and serving to direct air from within said receptacleto said passageway, flexible sealing means between said housing and said casing, means for supporting said unit from said casing so as to permit upward movement of said unit due to the air pressure difference on either side of said sealing means created by said fan, and resilient means reacting between said casing and said unit for resisting said upward movement. V

17. A vacuum cleaner comprising a. dust co1- lecting receptacle having impermeable walls and having a. passageway extending through the same', a casing within a part of said passageway, 55

either side of said sealing means created by said fan, and resilient means reacting between said casing and said unit i'or resisting said upward 70 movement.

AXEL ALBERT FORSBERG. 

